The exchange of gases and particles between the ocean and atmosphere can affect the Earth's climate by modifying the atmospheric concentrations of greenhouse gases and aerosol particles and by altering the oxidizing capacity of the troposphere. This cruise will include measurements of sulfur, carbon, nitrogen and halogen compounds in the ocean and overlying atmosphere in order to quantify the cycling of these compounds in the surface ocean and atmosphere and to calculate the exchange of these compounds between the ocean and atmosphere. Atmospheric aerosol measurements will be used to document the chemical, physical and optical characteristics of remote marine aerosols, investigate the relationships between these aerosol properties, and to determine the key physical and chemical processes controlling their formation, distrbution, and radiative properties.

This cruise is part of the International Global Atmospheric Chemistry Programís Aerosol Characterization Experiment (ACE-1). Shipboard measurements will be coordinated with aircraft and ground based measurements. The ship cruise track will consist of a trans-Pacific transit from Seattle to Hobart with a fueling stop in Hilo, HI. Seawater and air samples will be collected while the ship is underway and at daily CTD stations. The second leg of the cruise will be focused in the ACE-1 study area south of Tasmania and will include a stop at Macquarie Island.

CTD/rosette casts for carbon monoxide production and consumption rates and methyl halide distributions.

Ship Operations Contact:

Scientific Operations Contact:

Lt. John Herring

Dr. Timothy Bates (206-526-6248)

(206-553-4548)

Commander Dale Bretschneider (206-526-6813)

NOAA/PMC (PMC10

NOAA/PMEL (R/E/PM)

1801 Fairview Avenue East

7600 Sand Point Way N.E., Bldg. 3

Seattle, WA 98102

Seattle, WA 98115

1.0 Scientific Objectives

Aerosols and Climate -- Atmospheric aerosol particles affect the Earth's radiative balance both directly through the upward scatter of solar radiation and indirectly as cloud condensation nuclei (CCN). The natural aerosol derived from biogenic sulfur emissions has been substantially perturbed by anthropogenic aerosols, particularly sulfates from SO2 emissions and organic condensates and soot from biomass and fossil fuel combustion. The global mean radiative forcing due to the direct effect of anthropogenic sulfate aerosol particles is calculated to be of comparable magnitude but opposite in sign to the forcing due to anthropogenic CO2 and the other greenhouse gases. More uncertain is the radiative forcing due to the indirect cloud-mediated effects of aerosol particles. Although aerosol particles have a potential climatic importance over and down wind of industrial regions that is equal to that of anthropogenic greenhouse gases, they are still poorly characterized in global climate models. This is a result of a lack of both globally distributed data and a clear understanding of the processes linking gaseous precursor emissions, atmospheric aerosol properties, and the spectra of aerosol optical depth and cloud reflectivity. At this time, tropospheric aerosols pose one of the largest uncertainties in model calculations of the climate forcing due to anthropogenic changes in the composition of the atmosphere. Clearly, considerable attention must be focused on quantifying the processes controlling the natural and anthropogenic aerosol and on defining and minimizing the uncertainties in the calculated climate forcings. The Southern Hemisphere Marine Aerosol Characterization Experiment (ACE-1) is the first of a series of experiments that will quantify the combined chemical and physical processes controlling the evolution and properties of the atmospheric aerosol relevant to radiative forcing and climate. The objectives of this series of process studies are to provide the necessary data to incorporate aerosols into global climate models and to reduce the overall uncertainty in the calculation of climate forcing by aerosols. The goal of ACE-1 is to document the chemical, physical, and optical characteristics and determine the controlling processes of the aerosol in the remote marine atmosphere.

RITS -- Trace gases in the marine boundary layer affect the Earthís radiative and chemical balance by absorbing the long-wave radiation leaving the Earth (green-house gases) and by altering the oxidative capacity of the atmosphere. The concentrations of these chemically reactive and infrared-active trace gases are increasing in the atmosphere due to anthropogenic activities. There is considerable scientific evidence that the increasing atmospheric concentrations of these gases will lead to a global warming which could have disruptive consequences world-wide. Predicting future concentrations of these gases and their potential climatic effects requires an improved understanding of their atmospheric sources and sinks and the processes controlling their concentrations. The goals of the marine RITS program are:

1. to assess the oceanic sources and sinks of the radiatively and reactively important trace species,

2. assess the oceanic and atmospheric distributions and properties of the key species, and

3. to understand the processes controlling the oceanic and atmospheric concentrations and assess the sensitivity of these systems to anthropogenic and natural perturbations.

The Chief Scientist is authorized to alter the scientific portion of this cruise plan with the concurrence of the Commanding Officer, provided that the proposed changes will not: (1) jeopardize the safety of the personnel or the ship; (2) exceed the allotted time for the cruise; (3) result in undue additional expense; or (4) change the general intent of the cruise.

The following continuous measurements will be made aboard Discoverer during transit and while on station:

Atmospheric Chemical Measurements

Mass size distributions of nss sulfate, MSA, ammonium, and other major ions with a seven stage multi-jet cascade impactor. Sampling time periods will range from 12 to 24 hours. (Quinn & M.Hamilton, PMEL)

Mass size distributions of nss sulfate, MSA, ammonium, and other major ions with a six-stage hi-vol cascade impactor. Sampling times will range from 2 to 6 hours. (Quinn & Hansen, PMEL for Sievering, UC)

Sub- and super-micron nss sulfate, MSA, ammonium, and other major ions with a two stage multi-jet cascade impactor. Upper size cuts will be 1.0 and 10.0 mm diameter. Sampling time periods will be 4 to 6 hours. (Quinn, PMEL)

The ammonium to nss sulfate molar ratio from 10 to 600 nm diameter using thermal conditioning in conjunction with a TDMA. (Orsini, ITR)

The ship will be equipped with an NCAR Integrated Sounding System (ISS). This system consists of an UHF/VHF Doppler wind profiler, a radio acoustic sounding system (RASS), an Omega NAVAID-based sounding system, and a surface meteorological station. The multiple frequency wind profiler operates at several different frequencies in conjunction with a RASS to obtain temperature and wind profiles as well as precipitation distribution. The NAVAID upper-air sounding and surface observing system utilizes the Omega navigation signals to compute upper level winds. A commercial lightweight radiosonde is used to retransmit the received signals and to telemeter the measured pressure, temperature, and humidity back to the ISS station.

Air samples will be collected using equipment mounted on the forward part of the flying bridge and G-deck. A mast will extend approximately 8 meters above G deck for air sampling lines. Additional air sampling lines will run from the flying bridge to the oceanographic laboratories and laboratory van on G-deck port side. A compressor will be located on the starboard shelter deck to fill aluminum gas cylinders for carbon isotope samples. The compressor requires 30amps at 110 volts.

Ship and scientific personnel must constantly be aware of potential sample contamination. Work activities forward of the main stack must be secured during sampling operations. This includes the bow, boat deck forward of the stack, bridge deck and flying bridge. The scientists on watch must be notified of any change in ship course or speed that will move the relative wind abaft the ship's beam or if anyone needs access to the bow. The scientists on watch should also be notified when the ship enters a rain squall and when the rain subsides.

Continuous water sampling will be made from the ship's bow intake system. This system must be capable of delivering 100 liters per minute through the F deck piping. Seawater will be drawn off this line to the vans on G deck and to three sea/air equilibrators located on the F shelter deck starboard side. Care must be taken to prevent contamination from smoke, solvent, cleaning solutions, etc.

Continuous underway measurements of CO2 will be made from one of the headspace equilibrators on F deck utilizing a LICOR NDIR Analyzer. The instrument will be operated and maintained by the Survey Department in the same manner as during the previous TAO cruise.

4.2 Station Operations

A CTD cast will be made each day during Leg I. Atmospheric and surface seawater sampling will continue while on station. The ship will remain headed into the wind to prevent contamination from the ship's exhaust and vents. Again, extreme care must be exercised to prevent contamination of the air samples. The scientists on watch must be notified of any ship operation that will move the relative wind abaft the ship's beam.

CTD operations will be conducted by the survey department. Maximum cast depth will be 500m with most samples collected in the photic zone (5, 10, 15, 20, 30, 40, 50, 75, 100, 200, and 500 m). Water from the cast will be sampled for carbon monoxide (CO) concentrations, CO production and consumption rates, halocarbons, and chlorophyll. An internally logging fluorometer and irradiance meter will be attached to the rosette. Every third day an additional cast will be made to 150m to collect a large volume (all bottles) water sample. At these stations a vertical net tow will be made to 100m to collect plankton samples.

4.3 Kilaeua Operations

The plume from the Kilaeua volcano on the island of Hawaii will be monitored by satellite imagery. When Discover reaches the center of the plume along 160įW, the ship will turn into the wind and proceed slowly towards the volcano for a 24 hour sampling period. At the end of the sampling period, the ship will head for Hilo to refuel.

4.4 Balloon Launches

Atmospheric temperature, humidity and wind profiles will be obtained from rawindsondes released from the ship twice per day at 1100 and 2300 UCT. Additional rawindsonde launches will occur during intensive sampling periods. Constant density balloons will be launched during leg II to start the lagrangian experiments. In addition, approximately 15 ozonesondes will be released throughout the cruise. Balloons will be filled and launched from the balloon shack.

4.5 Macquarie Island Operations

At the beginning of Leg II, Discoverer will proceed directly to Macquarie Island to disembark scientists and equipment. The scientists will return to Hobart on the Australia supply ship at the conclusion of ACE-1.

4.6 ACE-1 Operations

ACE-1 measurements will be conducted from Discoverer, the Australian FRV Southern Surveyor, the NCAR C-130 aircraft, and ground-based stations at Cape grim, Macquarie Island, and Baring Head (New Zealand). Discovererís general operating area is shown in dotted box of figure 1. Discoverer shiptime during the ACE-1 intensive will be used for:

1. An areal survey of DMS emissions,

2. Chemical, physical and optical measurements of the atmospheric aerosol to address the local closure and process studies outlined in the ACE-1 Science and Implementation Plan,

3. Surface support for the aircraft Lagrangian experiments and column closure experiments. The ship will release balloons and tracers for the Lagrangian experiment,

The sequence of operations aboard Discoverer during the ACE-1 intensive will depend on the synoptic meteorological conditions, the locations of the major oceanographic frontal zones, and the status of the other observational platforms and therefore must remain flexible. It is anticipated that the above activities will be carried out simultaneously during most of the cruise. A tentative ship schedule is listed below:

15-18 November

Depart Hobart, transit to Macquarie Island.

18-20 November

Sampling south of the subantarctic frontal zone, measurement intercomparison with Macquarie Island.

20-27 November

Sampling south of the subtropical front and southwest of Tasmania. Provide ground support for Lagrangian experiments.

27-30 November

Atmospheric sampling upwind of Cape Grim for measurement intercomparison with land and aircraft platforms.

01-07 December

Sampling south of the subtropical front and southwest of Tasmania. Provide ground support for Lagrangian experiments.

07-14 December

Sampling north of the subtropical front, west of Tasmania. Atmospheric sampling upwind of Cape Grim for second measurement intercomparison with land and aircraft platforms. Transit to Hobart.

During Lagrangian support periods, constant density balloons will be filled and launched from Discoverer to mark an air mass. After the NCAR C-130 begins to follow this airmass, Discoverer will run downwind for 24 hours to sample surface seawater under the balloonís path. After 24 hours the ship will turn upwind and return to the Lagrangian starting point.

The following systems and their associated support services are essential to the cruise. Sufficient consumables, back-up units, and on-site spare parts and technical support must be in place to assure that operational interruptions are minimal. All measurement instruments are expected to have current calibrations and all pertinent calibration information shall be included in the data package.

(a) Navigational systems including high resolution GPS.

(b) CTD/rosette sampling system. The CTD system will be operated by ship's personnel. Specific requirements for this system are:

(d) Chemical reagents, compressed gases (approximately 120 cylinders), and liquid nitrogen (200 liters). A complete listing of all chemicals to be brought onboard is included in Appendix C. Material Data Safety Sheets will be provided to ship before any chemicals are loaded.

The Chief Scientist is responsible for the disposition, feedback on data quality, and archiving of data and specimens collected on board the ship for the primary project. The Chief Scientist is also responsible for the dissemination of copies of these data to participants on the cruise and to any other requesters. The ship will assist in copying data and reports insofar as facilities allow. The ship will provide the Chief Scientist copies of the following data:

Sightings log (position and speed) of other vessels

Autosal salinity analysis logs

Deck log

Weather observation sheets

Autosal calibration reports

Thermosalinograph calibration reports

CTD cast logs

CTD calibration reports

CTD data in ASCII format

Weather maps

The Chief Scientist will receive all original data gathered by the ship for the primary and piggy-back projects, and this data transfer will be documented on NOAA form 61-29 "Letter Transmitting Data". The Chief Scientist in turn will furnish the ship a complete inventory listing of all data gathered by the scientific party, detailing types and quantities of data.

The Commanding Officer is responsible for all data collected for ancillary projects until those data have been transferred to the projects' principal investigators or their designees. Data transfers will be documented on NOAA Form 61-29. Copies of ancillary project data will be provided to the Chief Scientist when requested. Reporting and sending copies of ancillary data to NESDIS (ROSCOP) is the responsibility of the program office sponsoring those projects.

6.2 Cruise report

The Commanding Officer is responsible for the preparation of the cruise report that is due at the Pacific Marine Center within 30 days of the completion of the cruise. The Chief Scientist will deliver his cruise evaluation to the Commanding Officer in time for inclusion in the overall cruise report.

6.3 Ship operation evaluation report

This report will be completed by the Chief Scientist and the Commanding Officer using the form provided for that purpose.

6.4 Foreign research clearance reports

A request for research clearance in foreign waters (Kiribati, Tokelau, Nieu, Cook Islands, New Zealand, Australia) has been submitted by PMEL. The Chief Scientist is responsible for satisfying the post-cruise obligations associated with diplomatic clearances to conduct research operations in foreign waters. These obligations consist of (1) submitting a "Preliminary Cruise Report" immediately following the completion of the cruise involving the research in foreign waters (due at ONCO within 30 days); and (2) ultimately meeting the commitments to submit data copies of the primary project to the host foreign countries.

Any additional work will be subordinate to the primary project and will be accomplished only with the concurrence of the Chief Scientist and Commanding Officer on a not-to-interfere basis.

The following ancillary projects will be conducted by ship's personnel in accordance with general instructions contained in the PMC OPORDER:

(a) SEAS Data Collection and Transmission

(PMC OPORDER 1.2.1)

(b) Marine Mammal Reporting

(PMC OPORDER 1.2.2)

(c) Sea Turtle Observations

(SP-PMC-2-89)

(d) Bathymetric Trackline

(PMC OPORDER 1.2.5)

7.1 Ancillary Global Drifter Project

The Global Drifter Center (GDC) is responsible for the deployment and maintenance of the Surface Velocity Program (SVP) drifter arrays. A part of that responsibility includes the examination of drifter life expectancy, and consequently the study of drifter failures.

The operating lifetime of SVP drifters has been greatly increased in the past through design changes determined by inspecting drifters recovered after a length of service. Recent design modifications include the addition of a barometric pressure sensor, which required additional batteries and gave rise to a slightly larger surface float. Eighty-one barometer drifters are being deployed in the Southern Ocean (deployment began in October 1994) and 110 more barometer drifters have been ordered, also for deployment in the Southern Ocean. The addition of barometric pressure sensors and the consequent design changes increases the need to recover several drifters for post-deployment inspections. Post-calibration is the only viable method to determine the stability of these sensors at sea.

Attempts will be made to recover SVP drifters if they are encountered in the ACE-1 operating area.

The Chief Scientist or his representative may have access to the ship's cellular and INMARSAT phones. During Leg I and II the chief scientist will communicate daily with the PMEL computer/internet system to upload and download mail files. During Leg II the chief scientist will communicate with the ACE operations center in Hobart at least twice a day to coordinate sampling on the various ACE-1 platforms. All official calls by the Chief Scientist will be charged to a UCAR purchase order with PMC that will be established for ACE operations. The anticipated INMARSAT costs of the ACE operational calls to and from the ship are between $10,000 and $15,000.

Meals for scientific personnel will be charged at the rate of $7.50 per day. NOAA form 75-90, "Authorization of Mess Obligations", will be provided by the vessel to account for meals. The Chief Scientist will provide the appropriate accounting codes for NOAA funded scientists. Non-NOAA funded scientists will pay the ship directly at the end of each month.

Radio transmission can interfere with several of the continuous data streams. If this becomes a problem, the Commanding Officer and Chief Scientist will work out a transmission schedule to minimize data interferences to the extent that vessel communication needs allow.